Nursing is a discipline focused on assisting individuals, families and communities in attaining, re-attaining and maintaining optimal health and functioning.

A nurse practices nursing as a profession. There are a number of educational paths to becoming a professional nurse and in many countries, nursing practice is regulated by law. Advanced practice nurses include nurses with advanced education, generally at the graduate school level. There also are nurse reseachers who have PhDs in nursing or other fields and study human responses to health and illness in many settings.

Nurses acknowledge that the nursing profession is an essential part of the society from which it has grown. The authority for the practice of nursing is based upon a social contract that delineates professional rights and responsibilities as well as mechanisms for public accountability. The American Nurses' Association (1980) has defined nursing as "the diagnosis and treatment of human responses to actual or potential health problems." Nursing diagnoses are unique, bearing little resemblance to medical diagnoses.

Nurses practise in a wide range of settings from hospital to visiting people in their homes. Nursing is the most diverse of all healthcare professions. It is a universal phenomenon appearing in some form in every culture.